The richest period in American literary history, the American Renaissance (1830–1865) produced Ralph Waldo Emerson, Henry David Thoreau, Walt Whitman, Herman Melville, Nathaniel Hawthorne, Edgar Allan Poe, and Emily Dickinson. A distinction is traditionally made between the so-called light or optimistic authors (Emerson, Thoreau, and Whitman) and the dark or gloomy ones (Poe, Hawthorne, and Melville), with Emily Dickinson, occupying a middle ground, shifting between the light and the dark. Optimistic themes included nature’s miraculous beauty, spiritual truths behind the physical world, the primacy of the poetic imagination, and the potential divinity of each individual. Pessimistic ones included haunted minds, perverse or criminal impulses, doubt, and ambiguity. Americans probed these themes with special intensity largely because of the nation’s Puritan heritage. Calvinist preachers from John Cotton through Jonathan Edwards had devoted their lives to probing ultimate questions about death, God, and human nature. When this metaphysical impulse collided with 19th-century skepticism and secularism, the result was literature that ranged from the exhilarating to the disquieting, from Emerson’s affirmations to the ambiguities of Hawthorne and Melville. The American authors were strongly influenced by foreign literature, from the ancients to the Romantics. This transnational influence mingled with the styles and idioms of an emerging popular culture that was distinctively American, divided between conventional, sentimental-domestic writings and sensational or grotesquely humorous ones. Integrating themes and images from this variegated popular culture, the major authors also projected in their works the paradoxes of a nation that promoted both individualism and union, that touted freedom but tolerated chattel slavery, that preached equality but witnessed widening class divisions and the oppression of women, blacks, and Native Americans. These oppressed groups produced a literary corpus of their own that was once neglected but that has assumed a significant place in the American canon.